Process for continuously distilling and cracking hydrocarbon oils



Jv W. COAST, JR

May 1s 1926. 1,585,233

PROCESS FOR CONTINUOUSLY DISTILLING AND CRACKING HYDROCARBON OILS duly14, 1919 2 Sheets-Sheet l I 1 I I 1 60/12 .Setizpng Pa 2- I five/afar-Ja/m I44 (maid/r May 18,1926. v 1 ,585,233 J. W. COAST, JR PROCESS F01CONTINUOUSLY DISTILLING AND CRACKING HYDROCARBON OILS Filed July 14;1919 2 Sheets-Sheet 2 [Hue/afar Ja/m 144 60463 J? m uffl Patented May18, 1.926

UNITED, STATE DOHERTY RESEARCH COMPANY, OF NEW YORK, N. Y., AGORZPORATIiQN OF'DELA- PATENT ounce.

7 JOHN w. coas r, an, or TULSA, OKLAHOMA, AssreNomBY mnsmi ASSIGNMENTS,r0

rnocnss FOR com'muous'LY pIsTILLINeAND CRACKING HYnRooA aBoN orns.

. Application filed July 14, 1919. Serial No. 310,856.-

My invention relates generally to the art of distilling liquids and moreparticu-larly to improvements in the treatment by destructivedistillation or cracking of relatively heavy or high boiling pointhydrocarbon oils for the purpose ofproducing therefrom lighter or lowerboiling point products.

The principal objects of my invention are, to provide a relativelysimple method or process which can be practiced continuously, therebyminimizing the time, labor and heating expense ordinarily involved inthe production of lowboiling point products; to

provide for the rapid and continuous elimi-.

nation from the material under treatment,

' of the residue or pressure still bottoms utilized in practicing amodification of my improved method.- i

which, it will be understood, consists principally of carbon and heavytar; further, to provide an improved method wherein the oil undertreatment is expanded or the pressure in thesystem isreduced to effectadistil'lation of the lighter fractions from the pressure tar passingfrom the still in the system and causing the heavy coke, carbon and thelike from the hydrocarbon to gravi tate to the bottom of a settling tankfrom whence they are eliminated and the lighter fractions thus producedreturned to the still for further cracking; further,to provide a processwhereln the reflux condensate is in direct contact with the heatedvapors arising from the still, thereby vmaterially raising thetemperature of 'said reflux. condensate, and further to-utilize the heatfrom certain of the intermediate boiling point products taken o'flfromthe body of oil under treatment. and the heatfrom the residuum fromthe body of oil undertreatment'to preheat the fresh supply-of crude oilthat is being delivered to the body ofoil under treatment.

A relatively simple apparatus for practicing my improved'method isillustrated in the accompanying drawings, in .Which Figure 1.is adiagrammatic view of the apparatus, parts thereof being in section-Figure 2 is a diagrammatic View of an apparatus which may "beadvantageously ing drawings, 10 designates "a boiler -like container forthe liquid under treatment,

said container being usually referred to as a still. This container orstill is, disposed above a fire chamber 11 heated in any suitable mannerand provided with an arch- 12 which directs the greater portion of theheat the still.

.By thus delivering the greatest heat to the within the chamber to therear portion of rearportion of the still, the liquid Within the latteris caused to circulate along the tioned in the lower portion of thestill. This I scraper comprises one or more'endless members 13,operating on sprocket wheels. 14 or the like, and said endless memberscarrying scraping devices 15- which are adapted to make direct contactwith the inner surface of the bottom of the still so as to scrape and 1move the coke and relatively heavy residue toward the rear end of saidstill;

- The preferred form of scraper utilized in the stilli's disclosed in mycopending application, Serial Number 421494, filed Nov. 3,

A. coke and residue discharge pipe 16 leads from the lower portion ofthe rear end of the still to the lower portion of a coke pot .of anupright cylinder or container having a pressure equalizing piped-6.Located adjacent to the coke pot17 is an expansion drum 19 provided nearits upper portion -17, the latter being preferably in the form with avertically disposed baflle plate 20 and f leading from the upper portionof the. coke pot to the upper portion-of this'expansion drum is;atubular connection 21 in which is located a pressure control valve 22.Located adjacent to the. expansion drum-is-an exchanger 23- and leadingto a coil 24 in the upper portion thereof from the upper, portion ofexpansion drum 19 isa tubular connection 25. Located in thelower-portion of the exchanger is a coil 26 and leading'fronr -Referringby numerals to theaccompany- J the lower portion of expansion jdrum' 19to tion 37 and leading from said pump to the upper portion of anexchanger 137 is a tubular connect-ion 38, the latter being providedwith a suitable valve 39 adjacent to said last mentioned exchanger..This exchanger 137 is connected to and projects upwardly from the still10 and mounted on top of said exchanger is a reflux air cooled condenser40 of suitable construction. Leading from tubular connection 38 to still10 is a branch pipe 41 in whichis located a valve 42. Leading fromreflux condenser 40 to a main con denser 43 is a tubular connection 44which serves as a vapor line, and arranged therein is a suitable valve45. Leading from the lower port-ion of the coil of the main condenser 43to the tank 32 is a tubular connection 46. Leading from a suitablesource of crude oil supply to the lower portion of exchanger 23 is asupply pipe 47.

In practicing my improved method with the apparatus above described, theoil to be treated is delivered to exchanger 23' through supply pipe 47and rising in said exchanger absorbs heat from the heated residuumpassing through coil 26 and which latter is located in the line fromexpansion drum 19 to receiving tank 28. This crude oil also absorbs heatfrom the expanded hydrocarbon vapors liquefying in coil 24 and theliquetied vapors discharging from the end of this coil mix With thecrude oil rising through exchanger 23. The heated crude oil or mixturefrom exchanger tank 23 is drawn through line 37 by pump 36 and forcedthrough line 38 either into exchanger 137 or directly into still 10through branch pipe 41.

Obviously, the delivery of this crude oil mixture to exchanger 137 orstill 10 is controlled by manipulation of valves 39 and 42. The heatingof still 10 is governed by the requirements of the product beingtreated, and, as heretofore stated, the heat ispreferably delivered tothe rear portion of the still in order to induce circulation of theliquid product along the bottom of the still toward the coke dischargepipe 16, and this circulation is materially assisted by the action ofthe endless scraper, the scraping members'15 of which drag over thebottom of the still, thereby continuously moving the pressure stillbottoms toward the discharge pipe 16.

Where the crude oil or mixture is deliverecl into the upper portion ofexchanger itsaaas 137 through pipe 38, it flows in relatively thin filmsto the still, and the vapors from the still bubble through it during itsdownward passage through the exchanger. The incoming oil has a coolingelitect on the vapors passing upwardly through said exchanger and thisabsorption of heat knocks back a certain proportion of the heavierhydrocarbons which would otherwise pass upwardly into the reflux aircooled condenser 40. The heat of the vapors at the same time causes thelightest portions of the fresh oil to be distilled off.

Assuming that the still is being operated under heat of approximately750 degrees F., the vapors enter exchanger 137 at approximately 725degrees F. and the temperature of these vapors is lowered to aconsiderable extent within said exchanger due to the dropping back ofthe cooled hetwier hydrocarbons from the reflux air cooled condenser 40,and the vapor passing through said last mentioned condenser leaves thesame and passes through vapor line 44 at approximately 450 degrees F.The pressure on these hot vapors is relieved as they pass the valve 45,and if the pressure tends to increase or decrease it may be rendereduniform by opening or closing the valve. The vapors in vapor line 44pass into condenser 43, wherein they are condensed and in the form oflighter benzines or lighter hydrocarbons, they pass through line 46 totank 32.

The coke and heavier hydrocarbons discharge from outlet pipe 16 intocoke settling pot 17 and the heavier portion of this residue isintermittently or continuously drawn off by proper manipulation ofvalved outlet 18. In ordinary practice, the taking oft of the heavierhydrocarbons through the outlet 18 is effected from four to six timesevery twenty-four hours. The lighter portion of the material within thecoke settling pot passes continuously through tubular connection 21 toexpansion drum 19. The pressure of the oil in the coke pot 17 isgoverned by the pressure control valve 22 which may be manually operatedtoward open or closed position to decrease or increase the pressure onthe oil.

The degree of pressure maintained in st il 10 and coke pot 17 depends onthe product being treated; for instance, the pressure required forordinary crude oil will be from seventy-five to one hundred pounds, andthe residuum in passing valve 22 drops to at mospheric pressure withinexpansion drum 1.9. The lighter hydrocarbons pass from expansion drum 19through line to coil 2t. in exchanger 23, and the heavier residuum inexpansion drum 19 passes through line 27 to coil 26 and from thencethrough line 29 .to receiving tank 28 and from whence it is eliminatedor removed from the system.

liquefying in coil 24 are to a great extent .ab-

sorbed by the crude oil passing upwardly through exchanger tank 23 andas the crude oil is thus heated, certain lighter vapors are released andpass through line 31 to condenser coil 30 wherein they are condensedinto unfinished gasoline and the latter passes through line 33 to tank32 or said unfinished gasoline can be taken off, through line 34.

My improved method can be. used for the treatment of crude oil, gas oil,or fuel oil,

and by virtue of the fact that the method can be practiced continuouslyand Without shutting down for the elimination of the' coke, carbon andthe like, the method has approximately twice the capacity of an ordinarybatch still or the so-called semicontinuous pressure still. Inasmuch asthe scraper is continuously operated while the method is beingpracticed, the heavier residuum in the still 10 is constantly beingWithdrawn. As a result of the reduction in pressure by means of valve 22in line 21, the coke forming material is caused to quickly drop to thebottom of expansion drum 19 and after passing through the exchanger tank23 to assist in heating the incoming crude oil, it passes to receivingtank 28. v

A slight modification of the method ust described can be accomplishedthrough the use of an apparatus constructed as illus trated in Figure 2,and in this apparatus the crude andgas oi] coming from exchanger 23passes through a pipe 38 to an ordinary pipe still 14-7, wherein it ispre heated before being raised from approximately 300 degrees F. toapproximately 650 degrees F. and when thus preheated, the oil I passesthrough line 48 to still 10. If desired, a line 49 may be led from thelower portionof exchanger 137 to line 38 for the purpose of conveyingthe reflux condensate from said exchanger 137 to line 38 and thus saidreflux condensate mixes with and 1s preheated with the crude oil mixturein pipe still 147.

The pipe still should be maintained at a suflicicnt temperature toslightly crack the crude oil or mixture passing through it, but

this temperature should, not be such as to produce any appreciableamount of carbon in the coils of the pipe still as this would seriouslyinterfere with the successful operation of the method. The pipe stillprovides a simple means for effecting prelimi-' nary cracking and at thesame time it relieves the main still of a certain amount of work andreduces to a corresponding degree the heat required for said main still.

My improved method can be Very economically practicedby'virtue of thefact that a comparatively small quantity of fuel is required for heatingpurposes and as the distillation and the cracking of the oil undertreatment is accomplished at one opera-. tion, the amount of equipmentnecessary for producing a given amount of merchant able product ismaterially reduced.

Thus it will be seen that I have produced a relatively simple and easilypracticed continuous method for the distillation and cracking of liquidhydrocarbons which involves the cracking of the oil under pressure in aheated still, the-return of the heavier condensates to the still throughthe use of'a suitable condenser, reducing the pressure of the lightervapors and condensing them under atmospheric pressure, thecontinuousremoval of the carbon and coke from the still, the delivery ofsaid carbon and coke to a suitable container, the settling of theresidue and the reduction of their pressure to evaporate. them by theirsensible heat, the condensation of the residue vapors by the coolingaction of fresh crude or gas oil passing to the still, and the that theillustration is merely diagrammatical and that any suitable apparatusmay be used for practicing the method set forth and hereinafter claimedand that tempera tures and pressures in .the still Will vary accordingto the product under treatment.

I claim: '1. The hereindescribed method of treating hydrocarbon oilwhich consists in sub jecting a body of oil to heat and pressure,drawingo'ff the heavier oil from therfirst body of oil to form asecondbody ofoil also maintained under pressure, andv reducing thepressure on the second body of oil to effect the distillation of aportion of said oil.

2. The hereindescribed method of treating hydrocarbon oil Which consistsin subjecting a body of oil to heat and pressure to release vapors fromthe oil, drawing off the heavier oil from the first body of oil andholding it under pressure, reducing the pressure-- on said ,heavier oilto efi'ect the distillation of a portion of said oil, then in: a body ofliquefy the same, and then returning the resultant liquid to the mainbody of oil for retreatment.

3. The hereindescribed method of treating hydrocarbon oils whichconsists'in subjecting a bot y of oil to heat and pressure separatelyrecovering released vapors from the oil, drawing oil the heavier oilfrom said body of oil and holding it under pressure, and reducing thepressure on the heavier oil to etlect a. separation ofits lighterconstituents from-its heavier constituents.

l. The hereindescribed method of treating hydrocarbon oils whichconsists in holdoil under heat and pressure in a still to distill' olfthe lighter tractionsof the oil, simultaneously drawing oft heavier oiland sediment such as coke from the bottom ot the body of oil in thestill to form a second body of oil and sediment, reducing the pressureon the oil in the second body to effect a distillation of a portion ofthe lower boiling point hydrocarbons contained in said body, andremoving seeiment from the second body.

5. The herein described method of treating oil which consists in rapidlydistilling the body of oil under pressure, withdrawing vapors andcondensing the said vapors under reduced pressure, withdrawing a residuetromthe body of oil and simultaneously separating the heavy carbonaceousmaterial and tar from the oil, separating the remaining oil into a lightand heavy traction, and returning the light fraction to the body of oilfor further treatment.

6. The hereindescribedmethod of treating ydroearbon oils which consistsin heating the oil to the cracking point under pressure to release thelow boiling point vapors, returning the heavier condensates to the bodyof oil under treatment, reducin the pressure of the lighter vapors andcon densing them under atmospheric pressure, removing from the body ofoil under treatment the carbon and heavier residue, reducing thepressure on the heavier residue to evaporate a portion of it by itssensible heat, and condensing the residue vapors by subjecting them tothe cooling temperatures of the oil supplied to the system fortreatment.

7. The hereindescribed method of treating hydrocarbon oils whichconsists in subjecting a body of oil to the simultaneous action of heatand pressure and distilling OK the lighter fractions and simultaneouslycracking the intermediate boiling point products, withdrawing a portionof the oil body under pressure, releasing the pressure on the saidportion to withdraw the intermediate boiling point products therefromand passing the said products into contact with the supply of oildelivered to the oil body under treatment in order to heat the saidsupply of oil and to distill the lighter hydrocarbons therefrom.

8. The hereindescribed method of treating hydrocarbon oils whichconsists in subjecting a body of oil to the simultaneous action ot heatand pressure to simultaneously distill elf the lighter fractions andcrack the intermediate boiling point products, rcloasing theintermediate boiling point products at atmospheric pressure to thesupply of oil delivered to the body of oil under treatment in order toheat said supply of oil and distill the lighter hydrocarbons therefrom,and utilizing the heat of the lighter hydrocarbons distilled from thebody of oil under treatment for heating the supply of oil as it isdelivered to the main body under treatment.

9. The hereindescribed method of treating hydrocarbon oils whichconsists in confining a body of oil and subjecting the same to theaction of heat and pressure of a sutlicient degree to rapidly distillofi the lighter hydrocarbons, separately vaporizing the intermediateboiling point products, providing a source of supply for the body of oilunder treatment, and causing the vapors of the intermediate boilingpoint products to pass through the fresh oil so as to utilize the heatof the distilled intermediate hydrocarbons for heating the oil supplyprior to its dclivery to the body of oil under treatment.

10. The hereindescribed method of treating hydrocarbon oils whichconsists in conlining a body of oil and subjecting the same to thesimultaneous action of heat and pressure of sullicient degree to rapidlydistill off the lighter fractions and to crack the intermediate boilingpoint products, removing the intermediate boiling point products inliquid form from the body of oil under treatment, reducing the pressureon the intermediate boiling point products to allow them to bevaporized, providing a source of supply of fresh oil and utilizing theheat of the distilled lighter products and inter1ne diate boiling pointproducts for heating the oil supply prior to its delivery to the body ofoil under treatment.

In testimony whereof I hereunto atlix my signature this 10th day ofJuly, 1919.

JOHN V. COAST, JR.

Sfi

